Estimate age of stroke - MRI

Age of stroke on MR (from Diagnostic Neuroradiology by Osborn)

Immediate
Absence of normal flow void
Intravascular contrast enhancement
Diffusion restriction (high DWI/low ADC)
Perfusion alteration
High DWI and normal T2/FLAIR is 62% sensitive and 78% specific for stroke <4.5hours old [Lancet Neurology 10/5/2011]

<12h
Sulcal effacement
Gyral edema
Loss of gray-white

12-24h
Hyperintensity on T2/FLAIR
Meningeal enhancement adjacent to infarct
Mass effect

1-3 days
Intravascular, meningeal enhancement starts to decrease
Early parenchymal enhancement
Striking signal abnormality on T1/T2
Hemorrhagic transformation may be evident

4-7 days
Striking parenchymal enhancement
Hemorrhage in 25%
Mass effect diminishing
Intravascular, meningeal enhancement disappears

1-8 weeks
Contrast enhancement often persists
Restricted diffusion ends at ~10-14 days
Mass effect resolves
Decrease in abnormal T2 signal sometimes
Hemorrhagic changes evolve

Months/Years
Encephalomalacic changes, volume loss
Hemosiderin staining if prior hemorrhage